// 边框颜色变量
$colors: (
  "grey": #c9c9c9,
  "d4d9de": #d4d9de
);

@each $direction in (left, right, top, bottom) {
  @each $colorKey, $color in $colors {
    /*
    .border-top-red {
      border-top: 1px solid red;
    }
    */
    .border-#{$direction}-#{$colorKey} {
      border-#{$direction}: 1px solid $color;
    }
  }
}
